Sumner was born on November 19, 1887 in Canton, Massachusetts. While hunting at age 17, Sumner was accidentally shot by a companion and as a result his left arm had to be amputated just below the elbow. He had been left-handed before the accident, after which he had to learn to do things with his right hand. Sumner graduated from Harvard University with a bachelor's degree in 1910 where he was acquainted with prominent chemists Roger Adams, Farrington Daniels, Frank C. Whitmore, James Bryant Conant and Charles Loring Jackson. After a short period of working in the cotton knitting factory owned by his uncle, he accepted a teaching position at Mt. Allison College at Sackville, New Brunswick, Canada; In 1912, he went to study biochemistry in Harvard Medical School and obtained his Ph.D. degree in 1914 with Otto Folin. He then worked as Assistant Professor of Biochemistry at Cornell Medical School in Ithaca, NY. Sumner married Cid Ricketts when she attended medical school at Cornell. They married on July 10, 1915 and had four children. They were divorced in 1930, but she kept her married name. Cid Ricketts Sumner went on to become an author, writing books that included Tammy Tell Me True, which was made into the movie Tammy and the Bachelor, and Quality, which became the movie Pinky. Cid Ricketts Sumner was murdered by their grandson, John R. Cutler, in 1970. In 1931 Sumner married Agnes Lundkvist. In 1943 they divorced; later that year he married Mary Beyer, with whom he had two children.
Research
It was in 1917 at Cornell where Sumner began his research into isolating enzymes in pure form; a feat which had never been achieved before. The enzyme he worked with was urease, which he isolated from jack beans. Sumner's work was unsuccessful for many years and many of his colleagues were doubtful, believing that what he was trying to achieve was impossible, but in 1926 he demonstrated that urease could be isolated and crystallized. He accomplished this by mixing purified urease with acetone and then chilling it; the chilled solution produced crystallized urease. He was also able to show by chemical tests that his pure urease was a protein. This was the first experimental proof that an enzyme is a protein, a controversial question at the time. His successful research brought him to full professorship at Cornell in 1929. From 1924 on his laboratory was located on the second floor of the new dairy science building, Stocking Hall, at Cornell where he did his Nobel Prize–winning research. In 1937 he succeeded in isolating and crystallizing a second enzyme, catalase. By this time, John Howard Northrop of the Rockefeller Institute had obtained other crystalline enzymes by similar methods, starting with pepsin in 1929. It had become clear that Sumner had devised a general crystallization method for enzymes, and also that all enzymes are proteins. Dr. Sumner sounded early warnings about the water fluoridation schemes, "We ought to go slowly. Everybody knows fluorine and fluorides are very poisonous substances and we use them in enzyme chemistry to poison enzymes, those vital agents in the body. That is the reason things are poisoned, because the enzymes are poisoned and that is why animals and plants die.”